Flow diagram for patient enrollment or exclusion in the study. After excluding patients who did not meet the inclusion criteria, those with no comprehensive microbiological study, those with a final diagnosis other than CAP, and those with negative microbiological diagnosis, we obtained 185 patients with CAP and isolation of at least 1 microorganism. We subsequently excluded 4 patients with atypical bacteria-involved CAP, all of which were Mycoplasma pneumoniae (1 M pneumoniae + E coli, 1 M pneumoniae + influenza A, 1 M pneumoniae + influenza A + influenza B + syncytial respiratory virus [RSV], and 1 M pneumoniae isolated), and a further 7 due to a bacterial yield of improbable CAP cause because of their low pathogenicity (2 from bacterial group [1 Enterococcus faecalis and 1 Staphylococcus hominis) and 5 from mixed (2 S. hominis + Adenovirus, 1 S. hominis + Virus influenza A + RSV, 1 Staphylococcus coagulase-negative + metapneumovirus, and 1 Morganella morgagnii + coronavirus]). We then had 174 patients with viral, bacterial and mixed pneumonia. A biomarker search could not be performed in three patients, and we finally included 171 patients in our study with both etiology and biomarkers.